To satisfy mobile telephony device users that wish to use the same mobile telephony device for two purposes, a feature has been developed for the Global System for Mobile Communications (GSM) standard called “Alternate Line Service” or “ALS”. ALS allows a single mobile telephony device to support two different destination numbers. More particularly, since all GSM mobile telephony devices operate in conjunction with a Subscriber Identity Module (SIM), commonly known as a SIM card, ALS allows a single SIM card to support two different destination numbers. Separation of work-related and personal telephone calls is a primary application for ALS.
Another telephony standard, called Code Division Multiple Access, or “CDMA”, also allows a single mobile telephony device to support two different destination numbers. CDMA telephony devices may have a dual-NAM feature or a multi-NAM feature offering users the option of registering the telephony device with a local number in more than one market. A NAM is a Number Assignment Module, the electronic memory in the cellular phone that stores the destination number and an electronic serial number.
A mobile telephony device that supports two, or more, different destination numbers, and, accordingly, is associated with two, or more, communication lines, can only have a single communication line active at one time. Typically, a series of key presses is all that is necessary to switch the active communication line from one communication line to the other.
For most mobile telephony systems, voicemail messages are stored by a central voicemail server. Often a caller is connected to the voicemail server responsive to a failure to complete a connection to a mobile telephony device, where the user of the mobile telephony device subscribes to a voicemail messaging service. Under typical (single communication line) circumstances, once a voicemail message has been stored at the voicemail server, the voicemail server sends an indication of the waiting voicemail message to the mobile telephony device. The mobile telephony device may, responsive to receiving such an indication, signal to the user that the voicemail server has at least one voicemail message waiting. For instance, the signal may be a persistent icon on a part of a display screen of the mobile telephony device. The user may then use the mobile telephony device to place a call to the voicemail server and review the waiting voicemail message. The voicemail server uses Calling Line Identification (CLID) to associate an incoming call with a voicemail box and, once the user is authenticated, presents the waiting voicemail message to the user.
Under circumstance related to having a voicemail message to retrieve from a telephony device configured to have two, or more, communication lines, the user will first have to determine with which of the communication lines the voicemail message is associated. If the user determines that the voicemail message is associated with the active communication line, the user may simply perform standard actions necessary to contact the voicemail server and review the waiting voicemail message. However, if the user determines that the voicemail message is associated with a communication line that is not active, the user must take the steps to make the communication line active before performing standard actions necessary to contact the voicemail server and review the waiting voicemail message. Upon completion of the call to the voicemail server, the user is required to take the manual steps necessary to switch back the originally active communication line, assuming that the originally active communication line is the preferred line at the time.
It appears that the act of accessing voicemail on a telephony device that is configured to have two, or more, communication lines may be considered somewhat onerous.